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| United States Patent |
6,260,040
|
|
Kauffman
, et al.
|
July 10, 2001
|
Shared file system for digital content
Abstract
A distributed client server system for managing and storing digital files
includes a digital library and a shared file system, wherein the digital
library further includes a library client, a library server including a
library catalog, and an object server and wherein the shared file system
includes a workstation with a local storage and a shared file server with
a shared file storage. The digital library maintains metadata about the
files in the shared file system, in a database in the library catalog. The
metadata for a file includes different names for different versions of the
file and a check-in status flag. A read operation is performed on the
shared file system by a user retrieving a file directly from the shared
file system. A write operation is performed by the user invoking a digital
library application, which in turn changes the status of the flag to
"checked-out". When a file is "checked-out" it can not be edited by any
other user. When the "checked-out" file is saved, it is saved under a new
name. When a user quits after editing the file, the status of the file is
changed back to "checked-in".
| Inventors:
|
Kauffman; Steven Victor (San Jose, CA);
Lewis; Lara Marie (Campbell, CA);
Willey; James Albert (Cupertino, CA)
|
| Assignee:
|
International Business Machines Corporation (Armonk, NY)
|
| Appl. No.:
|
002951 |
| Filed:
|
January 5, 1998 |
| Current U.S. Class: |
707/10; 707/9; 707/200; 709/203; 715/751 |
| Intern'l Class: |
G06F 017/30 |
| Field of Search: |
707/10,8,9,200,203
395/200.03
709/201,203,217
345/329,330,331
|
References Cited
U.S. Patent Documents
| 4875159 | Oct., 1989 | Cary et al.
| |
| 4887204 | Dec., 1989 | Johnson et al.
| |
| 4888681 | Dec., 1989 | Barnes et al.
| |
| 5043876 | Aug., 1991 | Terry.
| |
| 5088031 | Feb., 1992 | Takasaki et al. | 395/400.
|
| 5239647 | Aug., 1993 | Anglin et al.
| |
| 5293618 | Mar., 1994 | Tandai et al.
| |
| 5313646 | May., 1994 | Hendricks et al.
| |
| 5317729 | May., 1994 | Mukherjee et al. | 707/3.
|
| 5574898 | Nov., 1996 | Leblang et al. | 707/1.
|
| 5649185 | Jul., 1997 | Antognini et al.
| |
| 5649200 | Jul., 1997 | Leblang et al. | 395/703.
|
| 5678040 | Oct., 1997 | Vasudevan et al. | 707/8.
|
| 5838916 | Nov., 1998 | Domenikos et al. | 395/200.
|
| 5852435 | Dec., 1998 | Vigneaux et al. | 345/302.
|
| 5889942 | Mar., 1999 | Orenshteyn | 395/187.
|
| 5896506 | Apr., 1999 | Ali et al. | 395/200.
|
| 5920893 | Jul., 1999 | Nakayama et al. | 711/147.
|
| 5933824 | Aug., 1999 | DeKoning et al. | 707/8.
|
| 5970490 | Oct., 1999 | Morgenstern | 707/10.
|
| 6023706 | Feb., 2000 | Schmuck et al. | 707/200.
|
Other References
Gill et al "A case study of file system workload in a large-scale
distributed environment", ACM 1994, pp. 276-277.*
Kamita et al. A Database Architecture and Version Control for Work Group.
IEEE 1994, pp. 438-447.
|
Primary Examiner: Black; Thomas
Assistant Examiner: Le; Uyen
Attorney, Agent or Firm: Sughrue, Mion, Zinn, Macpeak & Seas, PLLC
Claims
What is claimed is:
1. A distributed shared file system for storing digital data comprising:
a shared file system having a shared file system interface, said shared
file system for storing shared user files;
a distributed client-server system having a distributed client-server
system interface different from said shared file system interface, said
distributed-client server system storing metadata related to said shared
user files; and
a workstation, wherein the workstation is separately connected to the
shared file system and the distributed client server system and the shared
file system is connected to said distributed client-server system,
wherein users can access said shared file system using said shared file
system interface,
wherein said users perform at least one of reading and copying operations
of said shared user files directly from said shared file system without
direct involvement of said distributed client-server system,
wherein upon an edit request by a user, the distributed client-server
system directs the shared file system to send a copy of a shared file from
the shared file system to the workstation,
wherein editing of said shared user files requires updating said metadata
in said distributed client-server system.
2. A distributed shared file system according to claim 1, wherein a
plurality of workstations are connected to the shared file system.
3. A distributed shared file system according to claim 1, wherein a
plurality of shared file systems are connected to the distributed
client-server system.
4. A distributed shared file system according to claim 2, wherein a
plurality of shared file systems are connected to the distributed
client-server system and to one or more of the plurality of workstations.
5. A distributed shared file system according to claim 3, wherein one or
more of the file servers, the workstations and the client-server system
are located remote to one another.
6. A distributed shared file system according to claim 4, wherein the
client-server system comprises a library client having a client storage
area, an object server having an object storage area, and a library server
including a library catalog, wherein the object server is connected to the
library client and library server, the library server is connected to the
object server and library client, and the library server is located
remotely with respect to the library client.
7. A distributed shared file system according to claim 1, wherein the
workstation is connected to the distributed client-server system through a
network browser.
8. A distributed shared file system according to claim 2, wherein the
workstation is connected to the distributed client-server system through a
network browser.
9. A distributed shared file system according to claim 3, wherein the
workstation is connected to the distributed client-server system through a
network browser.
10. A distributed shared file system according to claim 4, wherein the
workstation is connected to the distributed client-server system through a
network browser.
11. A distributed shared file system according to claim 5, wherein the
workstation is connected to the distributed client-server system through a
network browser.
12. A distributed shared file system according to claim 6, wherein the
workstation is connected to the distributed client-server system through a
network browser.
13. A method for reading from a distributed shared file system including a
file server having a file storage medium having a file recorded thereon, a
distributed client-server system having at least a client, an object
server, and a library server, and a workstation having a local storage
medium, wherein the workstation is separately connected to the shared file
system and to the distributed client server system, and wherein the shared
file system is connected to said distributed client-server system, the
method comprising:
(a) receiving a request for access to read the file;
(b) determining if the user has permission to read the file, said
determining being done based on metadata about the file stored in the
distributed client-server system; and
(c) copying the file directly from the file storage medium of the file
server to the local storage medium of the workstation if the user is
determined to have permission to read the file, said copying being
performed without direct involvement of the distributed client-server
system.
14. A method of editing and saving files from a distributed shared file
system including a file server having a file storage medium, a distributed
client-server system having at least a client, at least an object server,
a library server and a shared file management system employing a check-in
flag and storing files based on a naming convention, and a workstation
having a local storage medium, wherein the workstation is separately
connected to the shared file system and to the distributed client server
system, and wherein the shared file system is connected to said
distributed client-server system, the method comprising:
(a) sending an edit file request from the workstation to the shared file
management system of the distributed client-server system;
(b) in response to the edit file request the shared file management system
checking to determine if a user has edit permission for the file with
corresponding metadata stored in the distributed client-server system;
(c) in response to the edit file request, if the user is determined to have
edit permission, the shared file management system checking to determine
if the file is checked-out;
(d) the shared file management system, via said corresponding metadata
stored in the distributed client-server system, indicating the file as
checked-out if the user has edit permission and the file is not
checked-out and directing the file server to copy the file from the file
storage medium to the local storage medium;
(e) sending a save message to the shared file management system to save the
file to the file server if the file has been edited;
(f) in response to the save message the shared file management system
checking to determine if the file has been edited; and
(g) if the file is determined to have been edited the shared file
management system directing the file server to copy the edited file from
the local storage medium to the file storage medium and naming the edited
file with a name different from the file copied from the shared file
management system.
15. A method according to claim 14, further comprising:
(h) performing a quit operation after copying the edited file to the file
storage medium, comprising:
(h1) sending a quit message to the file management system;
(h2) the file management system saving the file, if a save message is
received with the quit message;
(h3) the file management system recording the name of the user and
comments; and
(h4) the file management system indicating the file as checked-in.
16. A computer program product for connecting a shared file system to a
digital library in a system that includes a workstation that is separately
connected to the shared file system and to the digital library, wherein
the shared file system includes a file server and a storage medium, and
the digital library system includes a client, an object server and a
library server, the computer program product including a computer readable
medium comprising:
a computer-readable distributed client-server system code;
a computer-readable shared file system code; and
a computer-readable workstation program code;
wherein the distributed client-server system code logically maintains a
version control system including a check-in status of a file and a
plurality of versions of the file with different versions having different
names;
wherein the shared file system code physically maintains the plurality of
versions of each file;
wherein, in response to performance of a read operation on the file, the
shared file system code causes the file to be copied directly to a local
storage unit of the workstation;
wherein, in response to performance of an edit operation on the file, the
distributed client-server system code is requested to provide the file,
and the distributed client server system code checks a check-in status of
the requested file, and either sends a message to the requester when the
file is already checked-out, or directs the file server to copy the latest
version of the requested file to the local storage unit of the workstation
and changes the status of the file to checked-out; and
wherein a save and quit operation is personnel by requesting the
distributed client-server system code to direct the workstation program
code to copy the file from the local storage unit to storage controlled by
the shared file system code under a new name, recording comments and the
user name along with the new name for the file and changing the status of
the file to checked-in.
17. A system according to claim 1 wherein said users perform editing
operations through the distributed client-server system.
18. A method of managing files in a distributed shared file system
including a workstation, a shared file system and a digital library,
wherein the workstation is separately connected to the shared file system
and to the distributed client server system, and wherein the shared file
system is connected to said distributed client-server system, wherein said
shared file system stores user files, and wherein said digital library
stores metadata relating to said user files, said method comprising:
(a) copying one of said user files, having a first name, to a local storage
unit in response to a request;
(b) indicating the file as checked-out when an editing operation is
performed by setting metadata associated with the file to reflect a
checked-out state;
(c) indicating the file as checked-in after completion of the edit
operation, by setting the associated metadata to reflect a checked-in
state; and
(d) saving the edited file in the shared file system under a second name,
different from the first name.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the use of a file management system for
storing digitized data as files in a shared file system. In particular,
the invention relates to a system and method using files shared by a
community of users while providing integrity, security and preventing data
corruption.
2. Description of the Related Art Computers have been used to manage
business related information for a long time. However, costs associated
with storage, communication and information processing prohibited the use
of computers to store and manage other kinds of data. When costs came
down, it became feasible to digitize and store other forms of data,
including digitized data. Digitized data primarily consists of digitized
visual images, audio and video, although is not limited to those types of
data. Advanced information management system structures are required to
store and manage digitized data.
The value of the digitized data is enhanced if it can be shared by multiple
users. Use of networks and other distributed systems have made it possible
to have seamless and transparent sharing of data across wide geographical
areas. However, management of shared data is an issue that has confronted
practitioners in this area.
One known way of sharing data among multiple users is by using a shared
file system. Data to be shared by two or more users is stored in files
which are then available in a transparent mode for access by all users. A
conceptual view of a conventional shared file system is shown in FIG. 1.
One or more workstations (101, 102, 103) are attached to one or more file
servers (110, 111). Each workstation has connected to it its own local
storage medium called a "local store" (120, 121, 122). Each file server
has a permanent storage medium (130, 131), such as a hard disk, attached
to it called a "file server store". The local store stores local files
which are accessible only to the workstation connected to it. The file
server store stores files that are to be shared by all the users of the
system.
An example of the use of a shared file system is a community of artists
creating an animation work. Individual artists use workstations for doing
their work. Their private files, containing data specific to their
individual work, are stored in their local store. Data which is commonly
shared by all the artists is stored in the file server store. Individual
artists can access common data from the shared file storage and
incorporate it into their own work.
In creating animated work several artists work separately and create
separate components. For example, one artist might work on animation of
human characters while another might work on animation of animals while
yet another artist works on the sound, background, etc. Finally, one or
more artists combine the separately created components and make further
additions to create the final product. A shared file system enables this
production methodology by allowing the separate components to be placed on
the shared file system. The artist doing the combined work accesses the
shared file system and extracts the separate components into the local
store of his workstation.
A shared file system provides several advantages for multiple users, such
as the users being able to access and refer to each other's data.
Different users can also incrementally work on a single application.
However, maintaining data integrity in a shared file system has been a
problem. When multiple users share a file, the data contained in the
shared file is susceptible to inadvertent corruption as well as willful
damage. This is particularly acute when all users have write permission.
Besides, when multiple users access the file at the same time, each can
change the file without knowledge of the others concurrently making
changes to the same file.
The utility of a shared file system can be enhanced considerably by
integrating it with a file management system. A particularly useful tool
is a file management system that is part of an overall distributed
computing environment. An important feature of such a file management
system is in providing version control.
Version control maintains an older version of a file with either a
different name or by employing an extra character in the file name. It
also can provide a checking mechanism by which only one user is allowed to
"check out" a file at a time. All other users are allowed to access only a
read-only copy of the file. The user that has checked out the file
conventionally has write permission for the file and is allowed to edit
the file and save the edited file under the preexisting file name. After
editing the file the user that had checked out the file has to check the
file back in. The copy of the file which is checked-in then becomes the
latest version of the file.
A distributed computing environment provides a seamless transfer of files
to the user. Though the files are stored in various geographical
locations, the user is able to access a file as if it is stored locally.
The physical transmission of the file from a different location appears
transparent to the user,
An example of a distributed system is a conventional client/server system.
A conceptual view of a conventional client/server system is shown in FIG.
2 and described in detail in U.S. Pat. No. 5,649,185 granted to Antognini
et al. which is incorporated herein by reference. It includes a library
server 210, one or more object servers (220, 221), and a library client
230. The library server, the object server and the library client, each
have permanent storage media associated with it. That is the library
server 210 has a library catalog 240, the object servers include object
stores 250, 251, and the library client includes a client cache 260. Also
a communication isolator allows the library server and library client to
communicate with one another without the need for an application program
in the client having to handle complex communication protocols. The
library server, object servers and clients are connected by a
communication network such as a wide area network or local area network.
The library clients are normally implemented on a workstation and the
library and object servers are implemented on a host processor which can
be a workstation or a main frame computer. Library clients send requests
to the library servers to store, retrieve and update objects stored in
object servers. They also send requests to query the object indices and
descriptive information stored in the library catalog.
Users are granted privileges for the use of the library system services. A
user desiring to use the library system conventionally does so via an
application program running in the client which sends a request for an
item to the library server. The library server checks the library catalog
to ensure that the user's name and password are valid and that the user is
permitted to secure the desired service.
However, the transfer of files from a different geographical location
involves overhead in terms of transmission time and resources. So if a
distributed file management system is integrated with a shared file
system, files will be transferred back and forth between the distributed
system and the shared file system. In the case of digitized audio and
video files, where the sizes of those files are extremely large, the
transmission cost and times can be prohibitive. Much of the back and forth
transmission of files is unnecessary because the users of a preexisting
shared file system are often in close geographic proximity.
The users of a shared file system have also been accustomed to using the
file system and its interface. Hence, the imposition of a new command
language on the user likely would require additional training. Therefore,
only essential aspects of a file management system forming part of a
distributed computing environment should be incorporated into an existing
shared file system.
SUMMARY OF THE INVENTION
It is an object of the present invention to solve the problems described
above by using a preexisting shared file system as part of a distributed
computing environment.
It is another object of the present invention to solve the problems of
shared file systems. That is, the present invention provides seamless
read-only capability to all users, so that all users can directly read and
use the files from the shared file system without going through a
centralized file management system.
It is another object of the present invention to provide write permission
for a file to only one user at a time, so that the integrity of the data
in the file is maintained.
It is yet another object of this invention to maintain the older versions
of a file with appropriate comments and the name of the user who made the
changes even after a new version of the file is created.
The present invention ensures that the users can directly read and copy
files from the shared file system at the same time, ensuring that the
write operation is performed through a centralized file management system.
To achieve the objects discussed above the present invention is directed
to a distributed shared file system for storing digital data, which
includes a shared file system, a distributed client server system and a
workstation. The workstation is connected to the shared file system and
the distributed client server system. The shared file system is connected
to the distributed client server system.
A preferred embodiment of the present invention includes a plurality of
workstations and a plurality of shared file systems. Another preferred
embodiment of the present invention is directed to a distributed shared
file system where all the connections are remote.
Yet another preferred embodiment of the present invention is directed to a
distributed shared file system as described above where the client server
system comprises a plurality of library clients each having a client
storage area, a plurality of object servers each having an object storage
area, a library server including a relational database and an index. The
plurality of object servers remotely connected to the plurality of library
clients and the library server is remotely connected to the plurality of
object servers and the plurality of library clients.
The present invention also is directed to a method for reading files from a
shared file system, forming part of a distributed computing environment
including a user making a read file request at a workstation; the
workstation determining if the user has permission to read the file; the
workstation displaying an error message to the user if the user does not
have the appropriate permission; and the workstation copying the file from
the file storage medium of the file server to the local storage medium of
the workstation.
The present invention also provides for a method of managing files in a
distributed shared file system using a check-in flag and a naming
convention for files, including copying the files directly from the shared
file system to local storage for a read operation bypassing the file
management system; the file management system indicating the file as
checked-out when edit operations are occurring; the file management system
indicating the file as checked-in after completion of the edit operation;
and the file management system saving the edited file with a new name and
retaining the older file.
Another aspect of the present invention relates to a method of editing
files forming part of a distributed computing environment, including a
local storage medium, the method including a user making an edit file
request at a workstation; the workstation sending the request to the
shared file management system of a distributed client-server system; the
file management system determining if the user has edit permission; the
file management system sending an error message to the workstation if the
user has no edit permission; the file management system determining if the
file is checked-out; the file management system sending a checked-out
message if the file is checked-out; the file management system indicating
the file as checked-out if the user has edit permission and the file is
not checked-out; the file management system directing the file server to
copy the file from the file storage medium to the local storage medium;
the file management system sending a message to the workstation when the
file is complete; the user sending a save message to the file management
system to save the edited file; the file management system determining if
changes have been made to the file in response to receiving the save
message; the file management system directing the file server to copy the
edited file from the local storage media to the file storage media; and
the file management system naming the edited file with a new name and
retaining the existing file.
The present invention also provides for a method of quitting the file after
a save operation including the user sending a quit message to the file
management system; the management system saving the file, if the user has
sent a save message with the quit message; the file management system
recording the name of the user and comments; and the file management
system indicating the file as checked-in.
The present invention provides a computer program product for connecting a
shared file system, to a digital library; wherein the shared file system
includes a file server and a storage medium; wherein the digital library
system includes a client, an object server and a library server; the
computer program product including a computer readable medium comprising:
a computer-readable distributed client server system code; a
computer-readable shared file system code; and a computer-readable
workstation program code; wherein the distributed client server system
logically maintains a version control system including the check-in status
of a file and a plurality of versions of the file with different versions
having different names; wherein the shared file system physically
maintains the plurality of versions of each file; wherein, a read
operation is performed directly by copying files from the shared file
system code to the local storage of the workstation; wherein, an edit
operation is performed by requesting the distributed client server system,
and the distributed client server system code checking the check-in status
of the requested file, sending a message back to the user when the file is
already checked-out, directing the file server to copy the latest version
of the requested file to the workstation local medium and changing the
status to checked-out; and wherein a save and quit operation is performed
by requesting the distributed client server system code, and the
distributed client server system code directing the workstation to copy
the file from the local storage medium to the shared file storage under a
new name, recording comments and the user name along with the new name for
the file and changing the check-in status of the file to checked-in.
BRIEF DESCRIPTION OF THE DRAWINGS
The above objects and advantages of the present invention will become more
apparent by describing in detail preferred embodiments thereof with
reference to the attached drawings in which:
FIG. 1 is a diagram showing a conceptual model of a conventional shared
file system;
FIG. 2 is a diagram showing a conceptual view of a conventional distributed
client/server system;
FIG. 3 is a diagram of a shared file system connected to a distributed
client/server system according to the present invention;
FIG. 4 is a flowchart depicting a read operation in a shared file system
connected to a distributed client/server system incorporating a file
management system;
FIGS. 5A and B are flowcharts depicting a write operation in a shared file
system connected to a distributed client/server system incorporating a
file management system;
FIG. 6 is a flowchart depicting a quit operation in a shared file system
connected to a distributed client/server system incorporating a file
management system; and
FIG. 7 depicts an example of a shared file system according to a preferred
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of a shared file system for digital content,
according to the present invention is described below in detail with
reference to the accompanying drawings.
FIG. 3. is a conceptual representation of an embodiment of the current
invention. Box 3A represents a shared file system. Workstations 310, 311
and 312 are part of a shared file system. Local stores 300, 301 and 302
are connected to the workstations 310, 312 and 312, respectively. File
servers 320 and 321 are part of the shared file system and shared file
stores 330 and 331 are connected to file servers 320 and 321,
respectively.
A digital library system 3B is a distributed computing environment with a
file management system. An embodiment of a digital library is described by
Antognini et al. A digital library is an example of a conventional
client/server system. Library clients 350 and 351 are part of the digital
library client/server system. The library clients 350 and 351 have local
stores 340 and 341, respectively. The digital library comprises two type
of servers; object servers 360 and 361 and a library server 390. Local
stores 380 and 381 are connected to the object servers. An index store 391
is connected to the library server 390. A tape archive 370 is connected to
the object servers 360 and 361.
The users of the shared file system interact with the system using
workstations 310, 311 and 312. Their local files are stored in the local
stores 300, 301 and 302, respectively. The shared files in the shared file
system are made available to the users by the file servers 320 and 321.
The shared files are physically stored in the shared file stores 330 and
331. The shared file system is connected to the library clients in the
digital library client-server system. That is, when the users interacting
with workstations 310, 311 and 312 require the use of the digital library,
they can invoke a digital library application program which accesses the
digital library system via the library clients 350 and 351. The local
files belonging to the users of the digital library are stored in the
local stores 340 and 341. The persistent objects that the users of the
digital library require are provided to them by the object servers 360 and
361. The persistent objects that need to be stored on permanent media are
stored in the digital library system in the object file stores 380 and
381. The object servers, under control of the library server 390, extract
objects from these object storage stores when they are required by the
users of the digital library. The local store 391 connected to the library
server contains a library catalog which preferably is a database
describing the contents of the files and the objects stored in the digital
library.
In the present invention metadata about the files stored in the shared file
system is stored in the database within the index store 391. Therefore,
the metadata of the files in the shared file system can be provided to the
users of the shared file system by invoking a library client application
on the workstations 310, 311 and 312. Also, the library server acts as a
control point for accessing and changing the metadata of the files in the
shared file system.
FIG. 4. depicts a flowchart detailing a read operation according to the
present invention. A user begins interacting with the shared file system
in 400. The user makes a read request at his workstation in 410. In 420
the shared file system determines whether the user has read permission for
the requested file. If the user does not have the required read
permission, a message is passed to the user in 421, indicating that the
user is denied access to the requested file. If the user has permission,
the requested file is transferred from file server store to the local
store in 422.
FIGS. 5A and 5B together depict a flowchart detailing a write operation
according to the present invention. A user begins interaction with the
shared file system in 510A. In 520A the user requests a file for a write
operation at his workstation, thereby invoking a digital library client
application. In 530A the library client sends the request to the digital
library server. The file management system in the library server checks
the metadata of the requested file, which is stored in the library server
local store, to determine if the user has write permission for the
requested file, in 540A. If the user does not have writer permission for
the requested file the library server indicates so and a message is sent
to the workstation indicating that the user is denied write permission, in
550A. If the user has write permission, the file management system, in
560A, determines whether the file is already checked out. If the file is
checked out, the library server sends a message back to the workstation
indicating that the file is in use, in 570A. If the file is checked-in,
then the library server, in 580A, changes the metadata of the file in the
database to indicate that the file is checked out. In 590A the library
server sends a message based on which the digital library directs the
copying of the file from the file server storage to the local store of the
user's workstation.
As shown in FIG. 5B, in 500B the digital library indicates to the user when
the copying is completed. In 510B the digital library enters an idle mode
where it waits for the user to issue a save command. After the user issues
a save command, in 520B, the digital library determines whether the file
contents have changed. In the case where the contents have not changed, in
530B, the digital library indicates to the user that the contents have not
changed. If the file contents have changed, in 540B, the digital library
names the file according to a predetermined naming convention, which is
different from the name of the original file retrieved from the digital
library. In 550B the library server preferably records the new filename,
user name, size and location of the file in the database as part of the
metadata for the file. In 560B the digital library directs the copying of
the file from the user's workstation local store to the shared file store.
FIG. 6 depicts a flowchart detailing a "quit" operation according to the
present invention. A user begins interacting with shared file system in
600. In 610 the user issues a quit command. In 620 the workstation
initiates a digital library application program which changes the metadata
of the previously checked-out file to indicate that the file has been
checked-in.
An example illustrating the use of the present invention is a group of
artists creating animated features using a shared file system to maintain
the digital artwork. Prior to using the present invention the artists
would have had to use a universal read/write access system to read the
files in a shared file system. Because of the problems caused by universal
read/write access, considerable time and artwork would be lost. The
present invention enables the artists' assets to be brought under the
control of a digital library, preferably as described by Antognini et al.
Here, the artists are allowed the use of the existing file system on a
"read only" basis. That is, for read operations, the artists will not
experience any changes from the preexisting shared file system that is
conventionally used.
For write operations, the system according to the present invention allows
artists to proceed only through the file management system within the
digital library system. Users wishing to modify and write to an existing
file will invoke a digital library application program, preferably through
a web browser. The digital library, in response to the digital library
application program, changes the "checked-in" status of the file to
"checked-out". The digital library then directs the shared file system to
make a copy of the requested file to the local store of the artists'
workstation. The digital library stores the name of the file, the
check-in-status of the file, the name of the user and the time. When
another artist requests the same file for editing purposes, the digital
library application invoked sends a message that the file is in use and
provides information identifying the artist who has "checked out" the
requested file. The digital library also informs the user that, if needed,
a read-only copy can be provided.
After an artist has completed modifying the file, a second digital library
application is launched. This second digital library application directs
the file to be copied back to the shared file system. After the artist has
completed the current session and invokes a quit command, the first
digital library application changes the check-in-status to "checked-in",
thereby making the file available to others for editing purposes.
FIG. 7 shows a block diagram for an alternative embodiment of the
invention. In this embodiment a web browser 701 is used. An example of a
commonly used web browsers is Netscape Navigator. The web browser
communicates with a web server 702, which is a standard HTTPD web server.
The web server communicates with a digital library adapter 710. The
digital library adapter 710 is connected to a shared file system 720 with
which it communicates. The digital library has available to it a set of
C++ objects which are part of the digital library class library 730, as
described in U.S. patent application Ser. No. 08/688,120 now U.S. Pat. No.
5,787,413, which is incorporated by reference herein. These objects
communicate with the digital library client 740, which in turn provides an
interface to the digital library.
The use of a digital library as a storage management system for performing
version control provides the users with several advantages. The users are
given the ability to collect and search on metadata concerning the files
stored in the shared file system. The digital library system is also
accessible via web browsers, thereby making the digital library
application program platform independent. The shared file system of the
present system handles all read-only requests without invoking the digital
library, thereby reducing the transmission time and transmission costs. It
also reduces the impact of going through the web server and other
communication channels that distributed systems usually impose.
The file management system according to the alternative embodiment of the
present invention can also be used as a source code control system, to
control versions of computer programs during program development. This
alternative embodiment also only minimally disrupts users that already use
a shared file system. The digital library system is visible to the users
of this alternate embodiment only as a small set of web applications which
are used when editing is required. This invention is also robust enough to
be extended to users of any shared file system.
Other modifications and variations to the invention will be apparent to
those skilled in the art from the foregoing disclosure and teachings.
Thus, while only certain embodiments of the invention have been
specifically described herein, it will be apparent that numerous
modifications may be made thereto without departing from the spirit and
scope of the invention.
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